Re: hdd + ssd

Stefan Ring
2015-10-23T21:34:03Z

On Fri, Oct 23, 2015 at 1:48 PM, Emmanuel Florac <eflorac@intellique.com> wrote:
> YMMV, but here's my take:
>
> * flashcache being a facebook internal dev, probably is the most
> largely deployed one. It's clearly production-ready.
>
> * EnhanceIO works fine but I haven't tested it thoroughly. It adds no
> signature to the drives so it can be added to existing filesystems
> (flashcache and bcache need reformatting). However that means that
> bad thing may happen if you're careless -- it's clearly targeted at
> always-on servers.
>
> * bcache works fine but the latest fixes haven't been backported, so
> you should probably use it only with latest (4.2, 4.3) kernels. It's
> not very mature yet but it's *friggin' fast*.
>
> * dm-cache is the easiest to set-up with the lvmcache command (if your
> distro is recent enough of course). Like very very easy. It's
> unfortunately the slowest of the pack, apparently. Doesn't need
> reformatting IF your existing FS already lives in a LV.

Very good summary, thanks! Do you also happen to know if all of these
retain cache contents across reboots?